In the midst of ongoing debate about Russia’s interference in the 2016 U.S. presidential election and elections in France, former President Barack Obama spoke on the phone with French presidential candidate Emmanuel Macron on Thursday.

“Former President Barack Obama gently waded back into international politics on Thursday, talking by phone with French presidential candidate Emmanuel Macron,” Politico reported.

Macron, who, like Obama, favors France’s remaining in the European Union, is in an almost neck-and-neck race with candidate Marine Le Pen ahead of the first round of French elections on Sunday.

Obama’s spokesman, however, denied that the phone call and Macron’s tweet to the former president following the phone call are an endorsement:

“An endorsement was not the purpose of the call, as President Obama is not making any formal endorsement,” Obama spokesman Kevin Lewis said.

“The main message I have is to wish you all the best in the coming days, and make sure, as you said, you work hard all the way through—because you never know, it might be that last day of campaigning that makes all the difference,” Obama said in the phone call.

“I will do my best, believe me,” Macron said. “So I will fight to the last minute, and we will keep in touch, and our teams will realize and organize a new contact and see how to work together if I’m getting to the run-off.”

The Hill reported that Macron initiated the call.

Lewis said:

President Obama appreciated the opportunity to hear from Mr. Macron about his campaign and the important upcoming presidential election in France, a country that President Obama remains deeply committed to as a close ally of the United States, and as a leader on behalf of liberal values in Europe and around the world.

On March 29, Sen. Richard Burr (R-NC), chairman of the Senate Intelligence Committee tasked with investigating whether Russia interfered with the U.S. presidential election last year, warned that Russia is interfering with the French election.

“What we might assess was a very covert effort in 2016 in the United States, is a very overt effort, as well as covert, in Germany and France,” Burr told reporters.

“I remind you that we’re within 30 days of the first French election, with four candidates,” Burr said. “It will go down to two candidates with a runoff in May.”

“I think it’s safe by everybody’s judgment that the Russians are actively involved in the French elections,” Burr said.